﻿using EU.Core.Common;
using EU.Core.Common.Extensions;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Newtonsoft.Json;
using System.Text;

namespace EU.Core.Extensions;

/// <summary>
/// 自定义中间件
/// 通过配置，对指定接口返回数据进行加密返回
/// 可过滤文件流
/// </summary>
public class EncryptionResponseMiddleware
{
    private readonly RequestDelegate _next;

    public EncryptionResponseMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        // 配置开关，过滤接口
        if (AppSettings.app("Middleware", "EncryptionResponse", "Enabled").ObjToBool())
        {
            var isAllApis = AppSettings.app("Middleware", "EncryptionResponse", "AllApis").ObjToBool();
            var needEnApis = AppSettings.app<string>("Middleware", "EncryptionResponse", "LimitApis");
            var path = context.Request.Path.Value.ToLower();
            if (isAllApis || (path.Length > 5 && needEnApis.Any(d => d.ToLower().Contains(path))))
            {
                Console.WriteLine($"{isAllApis} -- {path}");
                var responseCxt = context.Response;
                var originalBodyStream = responseCxt.Body;

                // 创建一个新的内存流用于存储加密后的数据
                using var encryptedBodyStream = new MemoryStream();
                // 用新的内存流替换 responseCxt.Body
                responseCxt.Body = encryptedBodyStream;

                // 执行下一个中间件请求管道
                await _next(context);

                //encryptedBodyStream.Seek(0, SeekOrigin.Begin);
                //encryptedBodyStream.Position = 0;

                // 可以去掉某些流接口
                if (!context.Response.ContentType.ToLower().Contains("application/json"))
                {
                    Console.WriteLine($"非json返回格式 {context.Response.ContentType}");
                    //await encryptedBodyStream.CopyToAsync(originalBodyStream);
                    context.Response.Body = originalBodyStream;
                    return;
                }

                // 读取加密后的数据
                //var encryptedBody = await new StreamReader(encryptedBodyStream).ReadToEndAsync();
                var encryptedBody = responseCxt.GetResponseBody();

                if (encryptedBody.IsNotEmptyOrNull())
                {
                    dynamic jsonObject = JsonConvert.DeserializeObject(encryptedBody);
                    string statusCont = jsonObject.status;
                    var status = statusCont.ObjToInt();
                    string msg = jsonObject.msg;
                    string successCont = jsonObject.success;
                    var success = successCont.ObjToBool();
                    dynamic responseCnt = success ? jsonObject.response : "";
                    string s = "1";
                    // 这里换成自己的任意加密方式
                    var response = responseCnt.ToString() != "" ? Convert.ToBase64String(Encoding.UTF8.GetBytes(responseCnt.ToString())) : "";
                    string resJson = JsonConvert.SerializeObject(new { response, msg, status, s, success });

                    context.Response.Clear();
                    responseCxt.ContentType = "application/json";

                    //await using var streamlriter = new StreamWriter(originalBodyStream, leaveOpen: true);
                    //await streamlriter.WriteAsync(resJson);

                    var encryptedData = Encoding.UTF8.GetBytes(resJson);
                    responseCxt.ContentLength = encryptedData.Length;
                    await originalBodyStream.WriteAsync(encryptedData, 0, encryptedData.Length);

                    responseCxt.Body = originalBodyStream;
                }
            }
            else
            {
                await _next(context);
            }
        }
        else
        {
            await _next(context);
        }
    }
}

public static class EncryptionResponseExtensions
{
    /// <summary>
    /// 自定义中间件
    /// 通过配置，对指定接口返回数据进行加密返回
    /// 可过滤文件流
    /// 注意：放到管道最外层
    /// </summary>
    public static IApplicationBuilder UseEncryptionResponse(this IApplicationBuilder builder)
    {
        return builder.UseMiddleware<EncryptionResponseMiddleware>();
    }
}
